Trailer brake control

1 . A method for determining a trailer brake magnitude for a trailer brake system of a trailer being towed by a vehicle, comprising:

determining connection of a trailer to a vehicle;

determining at least one trailer parameter relating to a size, shape or a weight of the trailer;

determining a weight of at least some things within the vehicle to enable determination of a weight of the vehicle including the things within the vehicle;

determining a trailer braking magnitude as a function of the at least one trailer parameter and the weight of the vehicle including the things within the vehicle; and

controlling the trailer brake system as a function of the determined trailer brake magnitude.

2 . The method of claim 1 wherein the at least one trailer parameter includes an estimated weight of the trailer, and the estimated weight of the trailer is determined by a load sensor of the vehicle.

3 . The method of claim 2 wherein the load sensor is a ride height sensor of a vehicle suspension system.

4 . The method of claim 2 wherein the load sensor is an inflated member located in a connection area between the vehicle and the trailer.

5 . The method of claim 1 wherein the at least one trailer parameter includes an estimated weight of the trailer, and the estimated weight of the trailer is determined by comparison of at least one vehicle acceleration when the trailer is determined to be connected to the vehicle with at least one vehicle acceleration when the trailer is not connected to the vehicle.

6 . The method of claim 1 wherein the at least one trailer parameter includes a length between a front end and a rear end of the trailer.

7 . The method of claim 6 wherein the at least one trailer parameter includes a location of an axle of the trailer.

8 . The method of claim 1 wherein the trailer brake magnitude is adjusted based on at least one road condition.

9 . The method of claim 8 wherein the at least one road condition includes one or more of a road surface type, an environmental condition that affects vehicle traction, and a slope of a portion of a road being traveled on by the vehicle.

10 . The method of claim 1 wherein the step of determining a weight of at least some things within the vehicle is accomplished with a load sensor of the vehicle, and wherein the load sensor is a ride height sensor of a vehicle suspension system, or wherein the step of determining a weight of at least some things within the vehicle is accomplished with one or more cameras or object sensors arranged to detect things within the vehicle.

11 . A method for determining a trailer brake magnitude for a trailer brake system of a trailer being towed by a vehicle, comprising:

determining connection of a trailer to a vehicle;

determining at least one trailer parameter relating to a size, shape or a weight of the trailer;

determining a trailer braking magnitude as a function of the at least one trailer parameter; and

controlling the trailer brake system as a function of the determined trailer brake magnitude,

wherein the at least one trailer parameter includes an estimated weight of the trailer, and the estimated weight of the trailer is determined by a load sensor of the vehicle, the load sensor is an inflated member located in a connection area between the vehicle and the trailer, and

wherein the estimated weight of the trailer is determined as a function of a pressure of the inflated member and a location of an axle of the trailer relative to the vehicle.

12 . A system for determining a trailer brake magnitude for a trailer being towed by a vehicle, comprising:

one or more sensors that provide an output from which a weight of a trailer can be estimated;

a control system communicated with the one or more sensors, and responsive to the output provided from the one or more sensors to determine a trailer brake magnitude as a function of the weight of the trailer; and

a trailer brake actuator associated with a trailer brake system and operable to apply a trailer brake of the trailer brake system, the trailer brake actuator being driven by the control system as a function of the determined trailer brake magnitude,

wherein a) the weight of the trailer is estimated by a load sensor of the vehicle, the load sensor is an inflated member located in a connection area between the vehicle and the trailer, and the estimated weight of the trailer is determined as a function of a pressure of the inflated member and a location of an axle of the trailer relative to the vehicle, or b) one or more sensors are provided that provide an output from which a weight of at least some things within the vehicle can be determined, and the trailer brake magnitude is determined as a function of the weight of the at least some things within the vehicle, or both a) and b).

13 . The system of claim 12 wherein the one or more sensors that provide an output from which a weight of a trailer can be estimated includes a load sensor that is part of a suspension system of the vehicle and includes one or both of a ride height sensor and a ride height adjustment device.

14 . The system of claim 12 wherein the one or more sensors that provide an output from which a weight of a trailer can be estimated includes a trailer size sensor that is a camera or a reflective sensor, and wherein the control system is connected with the trailer size sensor and the trailer brake magnitude is determined as a function of the output of the trailer size sensor.

15 . The system of claim 12 wherein the one or more sensors that provide an output from which a weight of a trailer can be estimated includes a trailer size sensor and wherein the estimated weight of the trailer is determined as a function of the output of the trailer size sensor.

16 . The system of claim 15 wherein the estimated weight of the trailer is determined at least in part as a function of a length of the trailer as determined from an output of the trailer size sensor, and the length of the trailer is a distance between a front end and a rear end of the trailer.

17 . The system of claim 16 wherein the output from the trailer size sensor enables determination of a location of an axle of the trailer relative to the vehicle.

18 . The system of claim 12 wherein the one or more sensors that provide an output from which a weight of at least some things within the vehicle can be determined include one or more load sensors of the vehicle.